Lean at Idle

[Goat Blower]

Mine does the same thing, and it's not right. In closed loop, your a/f should hover around 14.7, that's where it's supposed to be. Mine goes lean and the idle drops to 900rpm and it stumbles. I haven't had time to mess with it, it might be the removed honeycombs on my maf, I'll find out soon enough.